Presentation is loading. Please wait.

Presentation is loading. Please wait.

Tropical East Pacific Synoptic Variability in NCEP Reanalyses 1 and 2: Comparisons With TAO Winds Presented by Yolande Serra, University of Arizona EPIC.

Similar presentations


Presentation on theme: "Tropical East Pacific Synoptic Variability in NCEP Reanalyses 1 and 2: Comparisons With TAO Winds Presented by Yolande Serra, University of Arizona EPIC."— Presentation transcript:

1 Tropical East Pacific Synoptic Variability in NCEP Reanalyses 1 and 2: Comparisons With TAO Winds Presented by Yolande Serra, University of Arizona EPIC Workshop11-13 May 2005APL, UW

2 CMAP A month : JAS TAO buoys used for this study W100W20W140E60W 20N 10N 0 10S 20S In Situ TAO Data Native 10-min data smoothed to hourly, then sub-sampled to 4xdaily to match NCEP Reanalyses. Native 10-min data smoothed to hourly, then sub-sampled to 4xdaily to match NCEP Reanalyses. All available wind data from June-November All available wind data from June-November

3 NCEP/NCAR and NCEP/DOE Reanalyses 2.5°x2.5°, 4xdaily 1000 mb winds 2.5°x2.5°, 4xdaily 1000 mb winds June-November time period to match TAO data availability. June-November time period to match TAO data availability.  TAO data are incorporated into both products to the extent allowed by the model data assimilation routine (!)

4 Model Configurations (adopted from Hodges et al. 2003) NCEP/NCARNCEP/DOE Data assimilation3DVAR SatelliteNESDIS TOVS Upper AirCloud winds, Radiosondes, dropsondes, pibals Same as NCEP. SurfaceStations, buoy SpecialPAOB, FGGE, TOGA COARESame as NCEP. BoundaryReynolds SST, ECMWF sea ice, NESDIS snow Same as NCEP. PBLMonin-Obukhov (1974)Hong and Pan (1996) RadiationLacis and Hansen (1974) (SW); Fels and Schwarztkopf (1975) (LW) Chou (1996) (SW) ConvectionArakawa-SchubertSimplified Arakawa-Schubert

5 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) NCEP/NCAR (RA1) vs. TAO - V-wind Power Spectra NCEP/DOE (RA2) vs. TAO - V-wind Power Spectra 9°N 140°W 2°N 140°W 5°N 140°W9°N 140°W5°N 140°W 0°N 140°W 5°S 140°W2°S 140°W 5°S 140°W 0°N 140°W2°N 140°W Cycles per day 4-day

6 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) NCEP/NCAR (RA1) vs. TAO - V-wind Power Spectra NCEP/DOE (RA2) vs. TAO - V-wind Power Spectra 4-day 8°N 125°W5°N 125°W 2°S 125°W5°S 125°W 0°N 125°W2°N 125°W Cycles per day 8°S 125°W Cycles per day 8°N 125°W5°N 125°W 2°S 125°W5°S 125°W 0°N 125°W2°N 125°W 8°S 125°W

7 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) NCEP/NCAR (RA1) vs. TAO - V-wind Coherence 2 and Phase NCEP/DOE (RA2) vs. TAO - V-wind Coherence 2 and Phase 9°N 140°W 2°N 140°W 5°N 140°W9°N 140°W5°N 140°W 0°N 140°W 5°S 140°W2°S 140°W 5°S 140°W 0°N 140°W2°N 140°W Cycles per day 4-day

8 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) NCEP/NCAR (RA1) vs. TAO - U,V-wind Biases and Correlations NCEP/DOE (RA2) vs. TAO - U,V-wind Biases and Correlations 9°N 140°W 2°N 140°W 5°N 140°W 0°N 140°W 5°S 140°W2°S 140°W VU 9°N 140°W5°N 140°W 2°S 140°W5°S 140°W 0°N 140°W2°N 140°W SDOM VU VUVU

9 Mean Bias in Eastern Tropical Pacific - rough estimates! RA1RA2 UVUV Mean Bias, m s SDOM, m s

10 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) 850 mb winds regressed onto TD-filtered OLR at 7.5N, 130W, June-November

11 NCEP/NCAR meridional eddy advection by eddy winds at 1000 mb ∂(v’v’)/∂y [m s -2 ] Synoptic-scale u’·  H v’ is ~8x10 -5 m s -2 NCEP/NCAR advection of meridional eddy momentum by eddy winds at 1000 mb Momentum gained by eddies Momentum lost by eddies

12 Comparison of synoptic waves in AGCMs - Hodges et al (2003) Track density distributions of EWs NCEP/NCAR NCEP/DOE

13 Summary of Comparisons with TAO Less variance at synoptic frequencies. Less variance at synoptic frequencies. Large diurnal variability at some locations. Large diurnal variability at some locations. Significant coherence and in phase with TAO at synoptic and lower frequencies. Significant coherence and in phase with TAO at synoptic and lower frequencies. Potentially large differences in mean wind components. Potentially large differences in mean wind components. Greater or equal amount of variance at synoptic frequencies. Significant coherence but out of phase by as much as a quarter cycle (~1 day) at synoptic frequencies. Potentially large differences in mean wind components. RA1RA2

14 NCEP/NCAR (RA1) vs. NCEP/DOE (RA2) NCEP/NCAR (RA1) vs. TAO - U-wind Power Spectra NCEP/DOE (RA2) vs. TAO - U-wind Power Spectra 9°N 140°W 2°N 140°W 5°N 140°W9°N 140°W5°N 140°W 0°N 140°W 5°S 140°W2°S 140°W 5°S 140°W 0°N 140°W2°N 140°W Cycles per day 4-day


Download ppt "Tropical East Pacific Synoptic Variability in NCEP Reanalyses 1 and 2: Comparisons With TAO Winds Presented by Yolande Serra, University of Arizona EPIC."

Similar presentations


Ads by Google